feat: Add support for encoding parameter on read_excel

[mau21mau]

• closes 'ascii' codec can't decode byte 0xd1 in position 2: ordinal not in range(128) #23444
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[pep8speaks]

Hello @mau21mau! Thanks for updating the PR.

• There are no PEP8 issues in the file pandas/io/excel.py !

Comment last updated on November 05, 2018 at 14:00 Hours UTC

[jreback]

this would absolutely need a test

[codecov]

Codecov Report

Merging #23448 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #23448      +/-   ##
==========================================
+ Coverage   92.22%   92.23%   +<.01%     
==========================================
  Files         161      161              
  Lines       51191    51197       +6     
==========================================
+ Hits        47210    47220      +10     
+ Misses       3981     3977       -4

Flag	Coverage Δ
#multiple	90.61% <ø> (ø)	⬆️
#single	42.27% <ø> (ø)	⬆️

Impacted Files	Coverage Δ
pandas/core/arrays/timedeltas.py	93.75% <0%> (-0.56%)	⬇️
pandas/util/testing.py	86.64% <0%> (-0.2%)	⬇️
pandas/core/indexes/base.py	96.46% <0%> (-0.16%)	⬇️
pandas/core/arrays/datetimelike.py	96.1% <0%> (-0.06%)	⬇️
pandas/core/indexes/datetimes.py	96.41% <0%> (-0.03%)	⬇️
pandas/core/indexes/datetimelike.py	98.01% <0%> (-0.01%)	⬇️
pandas/core/indexes/api.py	99% <0%> (ø)	⬆️
pandas/core/frame.py	97.03% <0%> (ø)	⬆️
pandas/core/generic.py	96.81% <0%> (ø)	⬆️
pandas/core/series.py	93.87% <0%> (ø)	⬆️
... and 5 more

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[jreback]

this needs tests, also pls merge master

[jreback]

needs tests. ping if you want to keep working.